Cooling system for furnace walls



1933- 0. H. 'HEDRICH COOLING SYSTEM FOR FURNACE WALLS Filed July 6, 19312 Sheets-Sheet l INVENTOR OTTO H. Heomcn QZCI M (I /m0 A ITORNEYS.

I Nov. 21, 1933. o. H. HEDRICH COOLING SYSTEM FOR FURNACE WALLS 2Sheets-Sheei? 2 Filed July 6, 1931 INVENTOR OTTO H. Heomcu AT ORNEYS.

Patented v Nov. 21, 1933 COOLING SYSTEM FOR FURNACE WALLS Otto H.Hedrich, Altadena, Calif.

Application July 6, 1931. Serial No. 549,034

4 Claims.

This invention relates to improvements in furnaces and particularly tomeans for cooling the throat of the furnace during combustion.

At the present time fuel burners are provided with means for supplyingoil, gas or powdered coal, in the form of a spray which is admixed withair at the throat of the furnace. The throat is usually formed of a.circular body of tile especially designed to effect proper mixture ofthe fuel and air. Heat radiated from the flame ignited in the furnacebecomes very intense and eventually results in distortion or destructionof the tile or failure of the brickwork adjacent thereto necessitatingrepair or replacement in order to maintain proper combustion conditions.

In the case of certain fuels, destruction of the tile may sometimes becaused by impurities in the fuel, fluxing with the tile under theinfluence of high temperature and thus causing erosion go of the tile.-Distortion of the tile either from the difference in expansion betweenthe front and back thereof or from erosion due to impurities in the fuelor from any other cause results in a destruction of the circular shapeand especial 25 design of the tile and consequently disturbs a properadmixture of the fuel and air.

The present invention therefore, has for one of its objects to providean improved arrangement of tubular cooling means at the inner side ofthe throat of refractory material, and between thelatter and thecombustion-chamber of the furnace, which tubular means will serve toreenforce the refractory material, as well as absorb a suiiicient amountof the heat, to which the refractory material is ordinarily subjected,to prevent distortion or destruction of the same and prolong its periodof effectiveness.

Another object of the invention is to'provide improved means forsecuring the tubular cooling 40 means in place at the innercombustion-chamberend of the refractory throat.

A further object is to provide improved tubular cooling means forembracing the combustionchamber-ends of a series of tiles that form thethroat whereby to reenforce the tiles at the hottest part thereof.

' Other objects and advantages of the invention will become apparentduring the course of the following detailed description of theaccompanying drawings showing preferred embodiments of the invention andin which] Fig. l is a rear elevation of the throat of a furnace with theinvention applied thereto;

Fig. 2 is a transverse sectional view through a portion of a furnacewall and specially constructed throat embodying the invention;

Fig. 3 is a diagrammatic plan view partly in section of a furnace andboiler showing the circulation system;

Fig. 4 is a vertical sectional view through -a portion of a furnacewall, air register, fuel chamber and throat showing another form of theinvention;

Fig. 5 is a plan view in elevation showing the cooling device applied toseveral fuel openings;

Fig. 6 is a view similar to Fig. 5 showing a modification of theinvention;

Fig. '7 is a side view of the tube arrangement shown in Fig. 6;

Fig. 8 is a view similar to Fig. 5 of another modification of theinvention;

Referring to the drawings and particularly to Figs. 1-2, the numeral 10indicates the brick wall of the furnace provided with an opening 11 inwhich is mounted the throat l2 composed of a plurality of tiles 13,-eachhavinga curved symmetrical face 14 for facilitating or effecting theadmixture of air and fuel which pass therethrough.

The embodiment of the invention shown in Figs. 1 and 2 is one of thepreferred forms, and the tile throat is especially formed and designedto accommodate the tubes 1516 which are disposed toward the combustionchamber of the fur- 8 nace and adjacent the rear face of the tile throatmost of which is recessed as at 1'7 to accommodate an arc of the surfaceof the tubes. As indicated at 18 the upper and lower tiles are notrecessed as the tubes are bent to extend in ap- 9O proximate parallelismabove and below the upper and lower tiles.

The flange 19 of the fuel chamber, which is shown complete in Fig. 4, issecured to the furnace by means of the nuts and bolts 20 and the tubes15 are secured in proper position relative to the recess 17 of the tilethroat by the bolts 21, the ends of which are preferably welded at 22 tothe tubes. The bolts 21 extend outwardly through the tile to receive thenuts 23. The tile throat 12 is secured in place by means of the hookbolts 24, the hooked ends of which are received in recesses 25 in thetiles, and the screw threaded ends of the bolts receive the nuts 26. Itwill be noted that there is an annular space between the throat and thefurnace walls in which the gas seal ring 27, backed by an asbestosgasket, is inserted. Any other open space except that between the tubeand tile may be filled with fire clay or the like.

Referring to Fig. 3, it will be noted that pipes 28 and 29 are connectedat o and i respectively to the Water circulation system which is alsoconnected to the boiler tubes B. The tubes 15 and 16 are connected at 30to the pipe 29 and at 31 to the pipe 28 so that water will freelycirculate through the tubes around the tile throats and adjacent wallsof the furnace, it being noted that the water is introduced to the tubesfrom a point outside of the combustion chamber and is returned to thecirculation system after having passed downwardly through pipe 28 andthrough connection 31 and upwardly through tubes 15 and 16, connection30 and pipe 29.

In Fig; 4, I have shown the air register A having tapering walls leadingto the fuel chamber F which discharges into the throat of the furnacethrough the openings S. The fuel mixes with a rotating column of airadmitted through the air register A and the mixture is carried throughthe throat opening into the combustion chamber as explained in PatentNo. 1,576,537 to E. H. Peabody.

In this form of the invention, the tubes 15', 16, are held against theface of the throat 12 by means of the bolts 21' welded at 22' to thetubes. The bolts pass through the tiles and through the flange 19' ofthe fuel chamber to receive nuts 23', thus holding the parts together.The gas seal ring 27, backed by an asbestos gasket, is disposed betweenthe tile throat and the wall of the furnace. The tile throat does nothave the special recessed face 17 shown in Figs. 1 and 2, but the tubes15', 16, are disposed adjacent the inner face of the throat between theface and the combustion chamber, and the tubes may be connected to thecirculation system of the boiler so that the heat absorbed by the deviceand imparted to the water becomes a part of the boiler output aspreviously explained, or the tubes may be connected to a source otherthan the circulation system of the boiler.

The arrangement of the bolts 21, 21' is calculated not only to space thefluid conduits a given distance from the other parts of the burner butalso to center the tube with respect to the tile and to maintain thetubes concentric with the throat. The bolts also hold the fuel chamberand refractory tile in proper position.

In Fig. 5, I have shown a multiple arrangement of burners wherein theupper and lower throats 34 and 35 are served by the tubes 36 and 3'7which may be connected in the manner disclosed hereinbefore inconnection with Figs. 1-7, with a source of supply.

In Fig. 6, I have disclosed a modification wherein a single tube 40 isbent to the approximate size and shape of the throat 41 and then bentover itself as at 42 and continued down and around the throat 43 andthen bent upon itself at 44. The inlet and outlet ends of this tube maybe connected either to the circulation system of the boiler or to anexternal source of supply and discharge.

In Fig. 8, I have shown the tubes 45, 46, crossing each other at the topand bottom of each burner throat 47 as indicated at 48 where they may bewelded or otherwise secured together.

In all of the embodiments of the invention above described and shown inthe accompanying have shown the cooling devices connected to the 1 watercirculation system in Fig. 3, it should be apparent that if air is to beused the tubes may be connected to a combustion air fan, or an induceddraft fan, or to the wind box which surrounds the air register. If wateris used the tubes may be connected into the boiler line as shown or theymay be connected to a separate source of supply. Regardless of thespecific cooling fluid employed or the source of supply, it should beobvious from the foregoing that the cooling devices will absorb some ofthe heat radiated from the flame during combustion and thus preventabsorption of all of the heat radiated by the flame by the refractorymaterial, thus prolonging the life of the throat and the bricks adjacentthereto.

It is to be understood that the invention may be practiced in connectionwith various types of furnaces and that it is not dependent in any wayon the kind of fuel and of the particular fluid used as a coolingmedium.

I claim:-

1. In combination with a furnace having an opening through its wall fromthe outer side to its combustion-chamber, of refractory materialarranged in said wall-opening to form a throat with a fuel-opening andtubular cooling means embracing the throat of refractory material at theinner combustion-chamber end thereof to reenforce-said refractorymaterial and protect that inner end from distortion.

2. In combination with a furnace having an opening through its wall from.the outer side to its combustionchamber, of a series of tiles arrangedin said wall-opening to form a throat with a fuel-opening, tubularcooling means curved to embrace the inner ends of the throat tiles andmeans extending from the outer side of the furnace to and engaging thetubular means for holding the latter in place around the innerthroat-ends of said tiles.

3. In combination with a furnace having an opening through its wall fromthe outer side to its combustion-chamber, of refractory materialarranged in said wall-opening to form a throat with a fuel-opening,saidthroat of refractory material having a curved recess at its inner endwhich is spaced from but extends around said fuel-opening and tubularcooling means in the curved recess of said throat of refractory materialfor reenforcing and protecting said throat material at thecombustionchamber end thereof.

4. In combination with a furnace having an opening through its wall fromthe outer side to its combustion-chamber, of a series of segmental tilesarranged in said wall-opening to form a throat with a fuel-opening,saidtiles having curved recesses at their combustion-chamber ends andtubular cooling means seated in said tilerecesses to reenforce the innerends thereof.

OTTO H. -I-IEDRICH.

